/
createWebpackLessPlugin.js
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/
createWebpackLessPlugin.js
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/* eslint-disable class-methods-use-this */
const less = require('less');
const loaderUtils = require('loader-utils');
const pify = require('pify');
const stringifyLoader = require.resolve('./stringifyLoader.js');
const trailingSlash = /[/\\]$/;
const isLessCompatible = /\.(le|c)ss$/;
// Less automatically adds a .less file extension if no extension was given.
// This is problematic if there is a module request like @import "~some-module";
// because in this case Less will call our file manager with `~some-module.less`.
// Since dots in module names are highly discouraged, we can safely assume that
// this is an error and we need to remove the .less extension again.
// However, we must not match something like @import "~some-module/file.less";
const matchMalformedModuleFilename = /(~[^/\\]+)\.less$/;
// This somewhat changed in Less 3.x. Now the file name comes without the
// automatically added extension whereas the extension is passed in as `options.ext`.
// So, if the file name matches this regexp, we simply ignore the proposed extension.
const isModuleName = /^~[^/\\]+$/;
/**
* Creates a Less plugin that uses webpack's resolving engine that is provided by the loaderContext.
*
* @param {LoaderContext} loaderContext
* @param {string=} root
* @returns {LessPlugin}
*/
function createWebpackLessPlugin(loaderContext) {
const { fs } = loaderContext;
const resolve = pify(loaderContext.resolve.bind(loaderContext));
const loadModule = pify(loaderContext.loadModule.bind(loaderContext));
const readFile = pify(fs.readFile.bind(fs));
class WebpackFileManager extends less.FileManager {
supports() {
// Our WebpackFileManager handles all the files
return true;
}
// Sync resolving is used at least by the `data-uri` function.
// This file manager doesn't know how to do it, so let's delegate it
// to the default file manager of Less.
// We could probably use loaderContext.resolveSync, but it's deprecated,
// see https://webpack.js.org/api/loaders/#this-resolvesync
supportsSync() {
return false;
}
loadFile(filename, currentDirectory, options) {
let url;
if (less.version[0] >= 3) {
if (options.ext && !isModuleName.test(filename)) {
url = this.tryAppendExtension(filename, options.ext);
} else {
url = filename;
}
} else {
url = filename.replace(matchMalformedModuleFilename, '$1');
}
const moduleRequest = loaderUtils.urlToRequest(
url,
url.charAt(0) === '/' ? '' : null
);
// Less is giving us trailing slashes, but the context should have no trailing slash
const context = currentDirectory.replace(trailingSlash, '');
let resolvedFilename;
return resolve(context, moduleRequest)
.then((f) => {
resolvedFilename = f;
loaderContext.addDependency(resolvedFilename);
if (isLessCompatible.test(resolvedFilename)) {
return readFile(resolvedFilename).then((contents) =>
contents.toString('utf8')
);
}
return loadModule([stringifyLoader, resolvedFilename].join('!')).then(
JSON.parse
);
})
.then((contents) => {
return {
contents,
filename: resolvedFilename,
};
});
}
}
return {
install(lessInstance, pluginManager) {
pluginManager.addFileManager(new WebpackFileManager());
},
minVersion: [2, 1, 1],
};
}
module.exports = createWebpackLessPlugin;